1. Field of the Invention
The present invention relates to a horizontal cavity surface emitting laser device.
2. Description of the Related Art
Along with the development of information technologies, data transmission using optical fiber communication has been rapidly developed. Hitherto, the optical fiber communication technology has been mainly used in long-distance high-speed data transmission typified by a terrestrial backbone and submarine optical communication, an access communication network typified by fiber to the home (FTTH), and a metropolitan area network connecting the backbone and the access communication network. In recent years, along with the widespread use of the Internet and mobile phones, the transmission capacity has dramatically increased, and the optical fiber communication has spread even to a storage area network (SAN) and the Ethernet (trademark) (local area network: LAN) connecting in-bureau high-speed network devices. Further, the transmission rate has been shifted from conventional 10-Gbps base to 40/100-Gbps base, and an optical communication standard of a 100-gigabit Ethernet for 100-gigabit transmission was standardized on June, 2010.
Further, in recent years, the throughput of a high-end router used in a backbone system has reached 1 Tbps, and further expansion of the capacity is expected in the future. Therefore, optical interconnections hold great promise in order to effectively process large-capacity data in data transmission between those transmission devices (few meters to hundreds of meters) or in data transmission within an extremely short distance such as inside a device (few centimeters to tens of centimeters). A semiconductor laser device, which is a transmission light source of an optical module that transmits and receives an optical signal, is classified into three types depending on the combination of its cavity direction (vertical resonance or horizontal resonance) and a surface from which the laser light is emitted (edge emission or surface emission). The first type is a horizontal cavity edge emitting laser device, the second type is a vertical cavity surface emitting laser device, and the third type is a horizontal cavity surface emitting laser device.
In Japanese Patent Application Laid-open No. 2010-45066 (hereinafter referred to as Patent Literature 1), there is disclosed a semiconductor laser that utilizes distributed Bragg reflection to shorten an active region and suppress a temperature rise in the device. In Internal Patent WO2005/072224 (hereinafter referred to as Patent Literature 2), there is disclosed a single chip for bidirectional photonic operation, in which a laser and a detector are integrated on an epitaxial layer and which is configured to make an access to a single fiber. In Japanese Patent Application Laid-open No. 2007-5594 (hereinafter referred to as Patent Literature 3), there is disclosed an optical communication module of a surface emitting type, which is excellent in heat radiation performance and has lower power consumption. In IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 3, NO. 9, 1991, pp. 776-778 (hereinafter referred to as Non-Patent Literature 1), there are described room-temperature continuous oscillation characteristics of a horizontal cavity surface emitting laser including an optical waveguide including an InGaAsP active layer formed over an InP substrate, a reflecting mirror inclined at an angle of 45° and formed at an end portion of the optical waveguide, and a circular lens formed at a position on the rear surface of the InP substrate so as to be opposed to the 45° reflecting mirror.